1. Field of the Invention
This invention relates to temperature control systems and more particularly to a light weight portable temperature control unit integrating a variety of face and body pads that will conform to the various contours of the face and body to aid in the therapeutic treatment of sports injuries and other forms of trauma, to relieve post operative pain, and to control swelling, bruising and engorgement.
2. Description of Prior Art
After injury and/or surgery, it has been found that controlling the swelling that normally occurs aids in expediting healing. In particular, in the field of cosmetic surgery, the necessity of maintaining a constant temperature, in the range of 34.degree.-40.degree. Fahrenheit, is extremely important to reduce internal bleeding, bruising and swelling.
Localized temperature control of various areas and parts of the human body, after injury and surgery, requires the use of cumbersome heating pads, ice packs, frozen gels, etc. Refrigeration systems which are large and bulky and which possess additional heating elements to raise or control the temperature, have been used to maintain the body, or a portion thereof, have been used to maintain the body, or a portion thereof, at a temperature substantially below the body's normal temperature of 98.6.degree. F.
The use of ice packs, when taken directly from a freezer and not permitted to warm above 32.degree. F., have been found to induce frostbite. Additionally, upon placement on a patient, the ice pack begins to melt and warm up rather quickly, thereby providing a constantly changing temperature at the areas of contact.
Thus, the various cooling techniques presently in use fail to satisfactorily maintain a constant temperature on the desired body areas.
In addition to the requirement of maintaining a constant temperature on the selected areas, there is also a need for a body pad that will comfortably and securely fit the contours of the area being treated as well as a need for providing portability of the heating or cooling unit.
There have been a number of efforts made to meet the described heating and cooling needs.
U.S. Pat. No. 3,074,410 (Foster) discloses an apparatus for temperature control in which a person's skin is heated and cooled by a fluid heat exchange medium. The cooling means comprises a compressor, a heat exchanger, and a by-pass valve for directing the fluid medium either through or past the heat exchanger. A pump runs continuously and the valve shunts the liquid medium around the refrigerating device when cooling of the liquid medium is not required. The apparatus also has a first thermistor adapted to sense the body temperature and a second thermistor to measure the temperature of the pad. The exchange fluid circulates through a pad contacting the patient's body. An electrical bridge means allows for the activation of the cooling and heating means when the patient's temperature is higher or lower than normal. This device has the drawback of being heavy, having high power demands, and allowing only for limited adjustment and programming.
U.S. Pat. No. 3,744,555 (Fletcher) discloses a liquid cooling apparatus possessing an automatic control system. The temperature of the wall of the auditory meatus and four averaged, unweighted skin temperatures are used as input signals to an electro-pneumatic transducer to control a diverter valve in the liquid cooling loop of the liquid cooling garment. The cooling system comprises a circulation pump, a heat exchanger, and a diverter valve connected in a fluid loop. A by-pass line is provided in the loop connecting the inlet side of the heat exchanger with the diverter valve. The diverter valve may be connected to an electro-pneumatic transducer for operation of the diverter valve according to control signals from a controller. The diverter valve is positioned so that the proper proportion of heated and cooled fluid from the discharge side of the heat exchanger is combined for recirculation through a cooling garment. This device does not allow for long term programming of time and temperature, does not have a heating system, and does not allow for a broad range of temperature settings.
U.S. Pat. No. 4,338,944 (Arkans) discloses a therapeutic device comprising a sleeve for covering a portion of a patient's body and having a space to receive liquid, a device for circulating a liquid through the space of the sleeve, and a device for cooling and heating the circulated liquid. The sleeve may have an inflatable external chamber to apply pressure in the sleeve against the patient's body. The device may have an inflation mechanism comprising an air compressor and a pressure regulator in order to inflate the chamber through a conduit.
During operation of the device, the pump circulates the cooling and heating liquid through the conduit, the sleeve space, and a container wherein the liquid is cooled or heated. The cooling and heating system device comprises a plurality of thermoelectric cooling modules, a metallic container having a chamber to retain a liquid such as water or antifreeze, and a variable direct current power supply. The device may have a pair of thermostats which measure the temperature of the liquid in the circulating system.
When direct current is passed through the thermoelectric device, one side or face of the thermoelectric device is cooled while the other side is heated. A reversal of the direction of the current results in a reversal of the sides of the thermoelectric device which are heated and cooled. The direct current of Arkans, however, only allows for the change in voltage to control the temperature of the thermoelectric cooling modules.
U.S. Pat. No. 4,459,468 (Bailey) discloses a fluid circulating system designed for use with a thermal blanket or pad wherein heating and cooling transfer elements are positioned directly in the fluid within the reservoir tank, eliminating the need for condenser structures and the like. More specifically, a temperature transfer means including one or more thermal modules is connected to the tank and electrically interconnected to transfer plates directly exposed to the fluid within the interior of the reservoir tank. A standby switching mode is included to prevent circulation of the fluid through the thermal blanket by a pump structure until the fluid reaches a preselected temperature. A temperature sensor is also in direct exposure to the fluid in the tank and serves to direct the fluid back to a temperature control means. The temperature control means is in turn electrically connected by current regulating and activating means to the thermal modules whereby a continuous path of information flows between the temperature of the fluid being sensed to the temperature control means and back to the thermal modules for activation thereof in order to accomplish the desired temperature.
The temperature control means further includes an adjustable temperature selector to selectively indicate the desired temperature over a wide range such as 40.degree. to 105.degree. F. A meter provides a visual indication of the actual temperature within the tank. The proper current direction through the thermal modules through an automatic hot-cold logic circuit is activated to heat or cool the fluid. Because the transfer plates are in direct exposure to the fluid on the interior of the tank, the cooling device of Bailey is heavy. Additionally, the fluid in the tank takes an appreciable amount of time to either heat or cool.
U.S. Pat. No. 5,097,829 (Quisenberry) discloses a circulating system for automatically cooling or heating a temperature control fluid. The system includes a device for powering the cooling system with pulse width modulated electrical signals, a device coupled to the sensing device for calculating from the sensed temperatures an indication of the temperature of the fluid flowing within the blanket, and a device associated with the powering system for modifying the temperature of the fluid by controlling the pulse width modulation of the power supplied to the thermoelectric cooling device.
The invention includes a fully automatic microprocessor control system for controlling the temperature of a circulated fluid and monitoring the temperature variations over time. The invention also provides for an electronic controller for a temperature control fluid circulation system which is fully programmable and has a display system which allows periodic reprogramming of the system and monitoring of the operating conditions.
The output of the thermoelectric cooling device is controlled by a pulse width modulator for precisely controlling the temperature of the cooling block. The pulse width modulation is coupled to a shift register for controlling the pulse width modulation of the modulator through a bayonet type male connector. Lights indicate the need to add fluid to the system, when the system is ready to begin fluid circulation operation, and when the system is operating properly. The device contains a unitary heat exchange block and thermoelectric cooling devices.
The device also contains a further input provided by a voltage divider to precisely calibrate the inputs to the microprocessor at the factory so that the temperatures sensed at the inputs are very precisely calibrated in the microprocessor.
The temperature of the blanket is determined by a calculation of the mean temperature between the temperature of the fluid at the exit conduit and the temperature of the entrance fluid returning from the patient blanket at the fluid connection. Alternatively, the system may calculate an approximate blanket temperature by adding an experimentally determined set-off value to the temperature of the fluid in a return conduit measured at the sensor near the return conduit's entry into the reservoir.
U.S. Pat. No. 4,108,146 (Golden) discloses a relatively thin bendable thermal pack unit adapted to be molded to conform closely to the contours of a portion of the human body and to retain the molded shape once it has been positioned to circulate a thermal fluid to heat or cool adjacent skin areas to aid in healing and the like. The thermal pack unit of the invention includes a plastic web or sheet having at least one channeled space formed in a surface thereof to form a path for the circulation of the thermal fluid therethrough. The bendable pack unit is formed from two pieces. The first piece is a bendable plastic sheet or web made from a durable plastic material such as polyvinyl which can be easily and readily bent or formed to fit the contour of a predetermined portion of the human body. The bendable plastic sheet has a channeled interior surface having one or more channel spaces or paths formed therein. The channel spaces may be separated by raised pedestal portions or separators to form a network of interconnected channels or paths for circulating the thermal fluid.
U.S. Pat. No. 4,962,761 (Golden) discloses a thermal bandage for heating and cooling which readily conforms to the contours of a body portion to maintain the adjacent skin at a predetermined uniform temperature to aid in heating and the like. The bandage includes a thermal pack mounted to the conformable member with means to either heat or cool the conforming member.
The heat conductive material includes a heat conductive fluid contained within a thin pliable outer material. The outer material is fixed about its perimeter to the thermal pack so that the fluid is in direct contact with it. The thin pliable outer material may also act as a sterile dressing to cover the adjacent skin portion to prevent infection. The conforming material is made of a heat conductive thermoplastic material.
In one embodiment, the pack includes a base, upstanding perimeter walls and a fluid flow changer defined by the base, walls, and conducting surface. The chamber has at least one separator which defines a circuitous flow path through the thermal pack. The conductive surface, which may separate the thermal pack and conforming member, can be constructed of a plurality of separate conducting plates mounted to a thermal pack at the free ends of perimeter walls and separators.
Velcro-type fasteners can be used to attach the pads.
A peltier device may be used which permits both heating and cooling by the use of dissimilar materials and electric current.